feat: maintenance mode indicator for whitelisted ips

src/Twig/AppRuntime.php

@@ -180,6 +180,14 @@ class AppRuntime implements RuntimeExtensionInterface
         return $requestedRoute === $route;
     }
 
+    /**
+     * The attribute is set by MaintenanceModeListener, on the ip whitelist branch only.
+     */
+    public function isMaintenanceMode(): bool
+    {
+        return true === $this->requestStack->getMainRequest()?->attributes->get('_maintenance_mode_allowed');
+    }
+
     public function getEncodedReturnUrl(): string
     {
         $masterRequest = $this->requestStack->getMainRequest();